The invention relates in general to a stator for an electric polyphase motor, particularly a stepping motor with a ring housing and pole pieces arranged in star-like fashion which can be inserted therein and can be wound from the outside. More particularly the invention relates to a stator for a polyphase motor having axially integral pole pieces which are arranged in star-like fashion around a hollow cylinder and are inserted into the hollow cylinder.
In one known stator of this type (German Offenlegungsschrift No. 18 14 977) the pole pieces sit with their one end in a hollow cylinder of plastic; for this purpose, they extend into the hollow cylinder up to a certain radial depth, so that either a circular intermediate layer of plastic remains between the radial inner limit of the pole pieces forming the legs of the star and the air gap proper, or the hollow cylinder must be turned from the inside in a further operation in order to obtain a particularly small air gap between the legs and the rotor.
In motors having a hollow cylinder which extends to the bore diameter and, therefore, to the radial inner ends of the pole pieces forming legs of the star, the necessary space for the air gap is provided by removing plastic material, particularly flash formations, by separate finishing operations after molding.